Synthesis and characterization of high-quality In₂O₃ nanobelts via catalyst-free growth using a simple physical vapor deposition at low temperature

High-quality indium oxide (In₂O₃) nanobelts were successfully synthesized without catalyst at low temperature ranged from 600 to 850°C using a simple physical vapor deposition. To synthesize the In ₂O₃ nanobelts, we employed a simple reaction of thermally evaporated indium vapor in a wet oxidizing environment. The In₂O ₃ nanobelts have diameters in the range of 20-200 nm and lengths over several hundreds micrometer. The synthesized nanobelts indicate high-purity and single-crystalline cubic structure. Most of In₂O ₃ nanobelts have 〈100〉 growth direction but some nanobelts have 〈110〉 growth direction. Photoluminescence spectra under excitation at 325 nm showed a strong and broad emission at 570 nm with a shoulder at 630 nm related to oxygen vacancies. We suggest that the synthesis of the In₂O₃ nanobelts follows the self-assisted growth mechanism in our method.